1. Field of Invention
The invention relates to methods and apparatus for electromagnetic-based quality inspection of energy storage, for example batteries, supercapacitors, and fuel cells.
2. Description of the Related Art
The operating ability of chemical power sources is substantially determined by the quality of its structural components including cathode, separator, and anode. Inspection to monitor the quality of these structures allows removal of defective units which prevents use of faulty electrode units in the downstream technological component assembly operations, thus reducing system defects due to defective battery units.
Known in the art is a method of assessing quality of these structures by stabilizing the technological processes of preparing the initial products, applying them on a foil, and drying. Experience proves that even when the physico-chemical characteristics of the initial raw material components vary within a tolerable range, overall discrepancies may lead to the appearance of rejects. Therefore stabilization of the operating conditions when producing the structural components, and of their physico-chemical characteristics alone cannot provide adequate quality control for dry electrode units.
Any outer visual inspection is also not possible as the unit components are inaccessible. Opening of the coiled electrode structures for visual inspection is not viable since the active mass of electrodes for example the carbon, lithium-treated cobalt oxide, etc., deposited onto a current collector for example copper or aluminum electrode strip features high brittleness, and fractures during repeated deformations. Therefore, there is a need for anode and cathode strip integrity testing and inspection including continuity for coiled electrode units using noncontact and nondestructive testing methods.